Cooling systems may be configured in a carbon dioxide booster system. This system may cycle CO2 refrigerant to cool a space. The refrigerant may be cycled through a low temperature load, low temperature compressor(s), a medium temperature load, and medium temperature compressor(s). The system may also include a subcooler and an accumulator. The subcooler further cools the liquid refrigerant and the accumulator prevents the flow of any liquid refrigerant from load(s) into the compressor(s).